Spring for Rotation?
If you're like me and wanted to make a rotational spring C between points A and B, such that it can rotate around point B, then you can make this construction with three objects. Two icospheres (for example), one at point B and one at point A. A cylinder is your rotational spring, and goes between the points. You add a spring constraint between icospheres A and B. Affix the cylinder C and icosphere A together with a fixed constraint. Affix the cylinder C and icosphere B together with a generic constraint, with all translation axes limited to 0 - 0. Then attach B to whatever object your rotational spring needs to be attached to.